a) Field of the Invention
This invention relates to a colorant composition for lawns, and more specifically to a colorant composition which contains as a primary component a colorant effective not only for coloring lawns but also for promoting growth of the lawns and preventing aging of the lawns and which, when applied to color the lawns, the color so applied can remain for a long time and does not stain other articles through rubbing.
b) Description of Related Art
As lawns wither into a yellow or light brown color in winter, colorant compositions with green or blue pigments contained therein have conventionally been sprayed to keep the lawns look green.
In these colorant compositions, organic pigments and/or dyes such as copper phthalocyanine blue pigments and copper phthalocyanine green pigments have been employed for the purpose of coloring alone.
These conventionally-employed pigments and dyes are however intended merely to color lawns at their surfaces, and no physiological effects for plants are observed on their coloring components themselves.
In these conventional colorant compositions, emulsions of acrylate ester resins, vinyl acetate resins, ethylene-vinyl acetate resins or the like or emulsions of water-dispersible polymers, such as synthetic rubber latexes, are also used as adhesives for fixing coloring components on turfgrass.
Incidentally, an emulsion of a polymer generally cannot form polymer films at temperatures lower than its film-forming temperature, so that a coloring component, especially a pigment cannot be fixed on turfgrass. When a colorant is sprayed in winter, the temperature is often so low that films cannot be formed with a pigment enclosed therein unless a polymer the lowest film-forming temperature of which is lower than the surrounding temperature, or example, is 5xc2x0 C. or lower is used.
In general, a polymer the lowest film-forming temperature of which is low is still soft and tacky even after formation into films, and is hence accompanied by a potential problem that they may be rubbed to stain shoes and clothing or at golf courses, to stain equipments such as balls and clubs.
With a view to improving the film-formability of aqueous emulsion polymers at low temperatures, film-forming aids are therefore often used in combination. Illustrative of film-forming aids are alkyl ethers and phenyl ethers of glycols and acetates of such ethers, and benzene or naphthalene solvents containing hydrocarbon groups. These film-forming aids cause no problem when employed industrially, but they are not suited for being sprayed over nature-oriented objects such as lawns and moreover, are also accompanied by a problem from the standpoint of odor.
The present inventors have proceeded with an extensive investigation with a view to overcoming the drawback that, when lawns are colored with conventional colorant compositions at low temperatures, the colorant compositions are rubbed to stain golf balls and golf equipments and hence with a view to developing a lawn colorant composition the colorant of which acts not only to achieve coloring but also to exhibit physiological effects (growth-promoting and anti-aging effects) for the plant. As a result, it was found that the above object can be achieved by using, as an adhesive, a water-dispersed resin and a water-soluble resin in combination and also a coloring composition containing a specific blue pigment as a coloring component. Based on this finding, the present invention has now been completed.
To achieve the above-described object, the present invention provides a lawn colorant composition having rearing effects, said lawn colorant composition being composed of a pigment and an adhesive therefor, wherein the pigment comprises a blue pigment composed as a primary component of a compound represented by the following formula: MFe[Fe(CN)6] wherein M represents an alkali metal atom or an ammonium group, one of the two Fe atoms is a divalent ion, and the other Fe atom is a trivalent ion; and the adhesive comprises a water-dispersed polymer and a water-soluble polymer having compatibility with the water-dispersed polymer.
Even when the lawn colorant composition according to the present invention as sprayed over a lawn is rubbed at a low temperature as a result of its contact with an object, the lawn colorant composition does not stain the object. Moreover, the lawn colorant composition can achieve not only coloring of the lawn but also promotion of growth of the lawn and prevention of aging of the lawn.
The present invention will next be described in further detail by preferred embodiments.
The blue pigment for use in the present invention is a pigment which comprises, as a primary component, a compound represented by the formula: MFe[Fe(CN)6], and its preferred average particle size ranges from 0.03 to 0.20 xcexcm, more preferably from 0.05 to 0.10 xcexcm.
In the above formula, M represents an alkali metal atom, such as sodium or potassium, or an ammonium group, and one of the two Fe atoms is a divalent ion, and the other Fe atom is a trivalent ion.
The coloring component in the colorant composition according to the present invention may be composed solely of a pigment which comprises as a primary component the compound represented by the above formula. To an extent not impairing the object of the present invention, however, another inorganic pigment or an organic pigment or dye may also be used in combination.
The colorant composition according to the present invention is characterized in that it comprises the above-described coloring component and an adhesive and the adhesive is composed of a water-dispersed polymer and a water-soluble polymer.
Preferred examples of the water-dispersed polymer for use in the present invention can include polymer emulsions (or latexes) the lowest film-forming temperatures of which are in a range of from 0 to 100xc2x0 C., for example, vinyl acetate emulsion, vinyl acetate copolymer emulsions, acrylate ester polymer emulsions, acrylate ester copolymer emulsions, methacrylate ester polymer emulsions, methacrylate ester copolymer emulsions, and styrene copolymer emulsions. More preferred are synthetic resin emulsions the lowest film-forming temperatures of which are in a range of from 0 to 50xc2x0 C.
Examples of the water-soluble polymer for use in the present invention can include those having compatibility with the water-dispersed polymer, such as polyvinyl alcohol, acrylic acid polymers, acrylic acid copolymers, maleic acid resins, cellulose resins, starch, and chitosan.
The preferred proportion of the water-soluble polymer is in a range of from 1 to 30%, with a range of from 1 to 10 wt. % being more preferred, both based on the water-dispersed polymer (solid content).
When the colorant composition according to the present invention is stored over a long time, it is effective to use one or more of various surfactants as a dispersant for the pigment. From anionic surfactants, cationic surfactants and non-ionic surfactants, one or more surfactants can be selected for use in the present invention in view of the dispersibility of the pigment and also their compatibility with the water-dispersed polymer and water-soluble polymer. Non-ionic surfactants can be mentioned as particularly preferred surfactants, although the present invention is not limited to the use of such non-ionic surfactant or surfactants. Further, defoaming agents, antiseptics, fungicides and the like can also be added as needed.
Next, the present invention will be specifically described by Examples and Comparative Examples. It shall however be borne in mind that the present invention is not limited by the Examples. All designations of xe2x80x9cpartxe2x80x9d or xe2x80x9cpartsxe2x80x9d and xe2x80x9c%xe2x80x9d in the Examples are by weight.